Archives Of Health News Blog From Medicineworld.Org

August 18, 2006, 6:52 AM CT

How Acid Reflux Leads To Esophageal Cancer

A particular enzyme is significantly higher in cancer cells that have been exposed to acid, leading to the overproduction of hydrogen peroxide, and offering a possible explanation for how acid reflux may lead to cancer of the esophagus, as per a recent study in the Journal of Biological Chemistry.

The study observed that the enzyme NOX5-S is affected by exposure to acid and that it produces stress on cells, activating genes that lead to DNA damage. For the first time, scientists have outlined the signaling pathway from cells damaged by acid, to the progression of esophageal cancer. They believe the same process may happen in the body when cells are exposed to acid reflux.

"The role of acid is controversial. But we show that by exposing cells to acid for short periods of time, that affects a particular enzyme, triggering a chain of events that possibly leads to cancer of the esophagus. Now that we have a better understanding of the signaling pathway, we can possibly identify who is at risk of developing cancer by determining the levels of this enzyme," says senior author Weibiao Cao, a researcher at Rhode Island Hospital and an assistant professor of medicine and surgery at Brown Medical School.

The study looked at human cancer cells and biopsies from patients with Barrett's esophagus (BE), a condition where cells in the esophagus have been altered by gastroesophageal reflux disease (GERD), or acid reflux. Acid reflux is thought to bea major risk factor for cancer in people with Barrett's esophagus.........

Core Needle Biopsy Gives An Accurate Picture

The gene expression profile detected in the core needle biopsy of a breast tumour is representative of gene expression in the whole tumour. A study published recently in the open access journal Breast Cancer Research confirms the reliability of core needle biopsy as a tool in breast cancer diagnosis and prognosis. The study also shows that the gene expression profile of a core needle biopsy might be more accurate than the profile of a surgical sample taken from the same tumour, after the biopsy was carried out. As per the study results, the biopsy procedure seems to trigger the expression of genes involved in wound healing as well as tumour invasion and metastasis, thus modifying the gene expression profile of subsequent surgical samples.

Rosanna Zanetti-Dällenbach from the Women's University Hospital in Basel, Switzerland and his colleagues from Stiftung Tumorbank, OncoScore AG and University Hospital in Basel, analysed the gene expression profile of core needle biopsies taken from 22 women diagnosed with breast cancer. For each woman, they compared the biopsy expression profile with the expression profile of a surgical sample taken from the tumour subsequently to the core needle biopsy. Zanetti-Dällenbach et al. quantified the expression of 60 genes known to be involved in breast tumour development using a technique called reverse polymerase chain reaction (PCR). Zanetti-Dällenbach et al. also analysed the gene expression profiles of surgical samples taken from the breast tumours of 317 patients who did not undergo a core needle biopsy.........

Spinal Cord Injury Treatment Progress

The body's spinal cord is like a super highway of nerves. When an injury occurs, the body's policing defenses put up a roadblock in the form of a scar to prevent further injury, but it stops all neural traffic from moving forward.

Scientists from Case Western Reserve University, Drexel University and the University of Arkansas bypassed this roadblock in the spinal cord. First, the scientists regenerated the severed nerve fibers, also called axons, around the initial large lesion with a segment of peripheral nerve taken from the leg of the same animal that suffered the spinal injury. Next, they jump started neural traffic by allowing a number of nerve fibers to exit from the end of the bridge. This was accomplished, for the first time, by using an enzyme that stopped growth inhibitory molecules from forming in the small scar that forms at the exit ramp of the bridge, where it is inserted into the spinal cord on the other side of the lesion. This allowed the growing axons to reconnect with the spinal cord.

Jerry Silver, a professor of neurosciences at the Case School of Medicine, was senior author among the scientists reporting in the Journal of Neuroscience article, "Combining an Autologous Peripheral Nervous System 'Bridge' and Matrix Modification by Chondroitinase Allows Robust Functional Regeneration beyond a Hemisection Lesion of the Adult Rat Spinal Cord." The other scientists were John Houle, the lead author, and Veronica Tom (a Case alum) from Drexel University College of Medicine; and Gail Wagoner and Napoleon Phillips from the University of Arkansas.........

Some video games promote sociability

Hang in there, parents. There is some hopeful news on the video-gaming front.

Scientists have observed that some of the large and hugely popular online video games eventhough condemned by a number of as time-gobbling, people-isolating.

monsters actually have socially redeeming qualities.

In theory, anyway.

After examining the form and function of what's known in the trade as.

MMOs massively multiplayer online video games an interdisciplinary team of.

scientists concludes that some games "promote sociability and new worldviews."

The researchers, Constance Steinkuehler and Dmitri Williams, claim that MMOs function not like solitary dungeon cells, but more like virtual coffee shops or pubs where something called "social bridging" takes place. They even liken playing such games as "Asheron's Call" and "Lineage" to dropping in at "Cheers," the fictional TV bar "where everybody knows your name."

"By providing places for social interaction and relationships beyond the workplace and home, MMOs have the capacity to function much like the hangouts of old," they said. And they take it one step further by suggesting that the lack of real-world hangouts "is what is driving the MMO phenomenon" in the first place.........

All Tobacco Bad For The Heart

A major Canadian-led global study has observed all forms of tobacco exposure, whether that be smoking, chewing or inhaling second hand smoke, increase the risk of heart attack.

The study by professors Salim Yusuf and Koon Teo of the Michael G. DeGroote School of Medicine at McMaster University and Hamilton Health Sciences in Hamilton, is published in this week's issue of The Lancet.

In collaboration with colleagues from 52 countries, they calculated the risk of heart attack for various forms of active tobacco use (both smoking and non-smoking) and second hand smoking in all areas of the world. The INTERHEART study included data from more than 27,000 people in 52 countries. In their calculations, the researchers accounted for other lifestyle factors that could affect the heart attack risk, such as diet and age.

They observed that tobacco use in any form, including sheesha smoking popular in the Middle East and beedie smoking common in South Asia, was harmful. In comparison to people who had never smoked, smokers had a three-fold increased risk of a heart attack. Even those with relatively low levels of exposure of eight to 10 cigarettes a day doubled their risk of heart attack. Each cigarette smoked per day, increased the risk by 5.6 per cent.

However, the scientists did find that the risk of heart attack decreased with time after stopping smoking. Light smokers, those who consume fewer than 10 cigarettes a day, benefit the most. They have no excess risk three to five years after quitting. By contrast, moderate and heavy smokers of 20 or more cigarettes a day still had an excess risk of around 22 per cent, 20 years after quitting.........

Cause of Ischemic Stroke Analyzed

In contrast to traditional beliefs that stroke-causing clots derived from arterial and cardiac sources are distinctly different, a new UCLA study shows they are composed of similar components.

Scientists studied clots removed from the brain blood vessels of 25 stroke victims. The clots were retrieved during therapy using a novel mechanical clot-retrieval device called the MERCI (Mechanical Embolus Removal in Cerebral Ischemia) Retriever. The removed clots were analyzed under the microscope to compare their component structures.

"Unexpectedly, no two retrieved clots looked the same, even though all were constructed from the same basic components of fibrin, white cells and red blood cells," said lead author Dr. Victor Marder, professor of hematology and oncology at the David Geffen School of Medicine at UCLA and a UCLA Stroke Center member. "The same components were involved in both the newly formed and mature, enlarging clots. Red blood-cell accumulations had previously been considered to dominate the structure of clots that formed within a heart chamber, but our results suggest that red cells often accumulated on clots after impaction in the brain artery".

The findings could lead to better therapies to prevent clots, clear blockages and reverse strokes in the crucial first hours after they occur.........

Botox Injections May Improve Facial-wound Healing

Botulinum toxin, the same Botox used to treat facial wrinkles, helps facial wounds heal with less scarring, as per results of a study reported in the recent issue of Mayo Clinic Proceedings.

David Sherris, M.D., professor and chair of the Department of Otolaryngology at the University at Buffalo is senior author on the research.

"This study is the first blinded trial demonstrating that injecting Botox (the trademark name for botulinum toxin) when we close a facial wound results in less visible scars," said Sherris, an ear, nose and throat specialist who came to UB from the Mayo Clinic in 2004.

"This study is the culmination of work that Dr. Holger Gassner and I started at Mayo Clinic about seven years ago. The reason this works is because wide scars are the result of the local muscles pulling the wound apart during the healing phase," he said. "Botulinum toxin temporarily weakens the surrounding muscles, thereby lessening the pull on the wound during the acute healing phase of the first 2-4 months".

The trial involved 31 patients who had sustained wounds to the forehead or were having elective surgery to remove skin cancers of the forehead. This area was chosen because it is especially susceptible to scarring, and because using Botox in this area has been shown to be safe and effective.........

Structure of key enzyme in plague bacterium

Ribbon rendering of the structure of AC-IV in Yersina pestis

Scientists at the National Institute of Standards and Technology (NIST) have solved the structure of a key enzyme from the bacterium responsible for plague, finding that it has a highly unusual configuration. The results may shed light both on how the bacterium kills and on fundamental cell signaling processes.

The NIST team determined the three-dimensional shape of class IV adenylyl cyclase (AC), an enzyme found in plague bacteria -- Yersinia pestis -- by purifying and crystallizing the protein and using X-ray crystallography at the Center for Advanced Research in Biotechnology to resolve its configuration. Adenylyl cyclase is a fundamental enzyme found in one form or another in organisms ranging from bacteria to mammals. It synthesizes cyclic AMP (cAMP*), an important signaling molecule that in turn triggers a variety of cellular processes. Six distinct classes of AC are known, playing a wide variety of roles. AC-II is part of the anthrax bacterium's killing mechanism, for example, while AC-III triggers adrenaline release in humans.

Shape plays an essential role in determining the biological function of a protein, but it's very difficult to determine for such large molecules. Three-dimensional structures are known for only two other forms of AC. The NIST experiments revealed that AC-IV has a shape completely different from the other two known shapes. AC-IV folds into a rare form of a barrel-like shape previously seen in only three other unrelated proteins.........

Cohabiters Are Traditional

Eventhough cohabitation outside of marriage is still considered to be an alternative lifestyle, working-class cohabiters are quite conventional when it comes to advancing their relationship, pursuing careers and doing housework, says Cornell sociologist Sharon Sassler.

Most of the 30 cohabiting working-class couples interviewed for the study still comply with traditional patterns throughout their relationships, including the initiation of the first date, moving in together and discussing marriage, Sassler said. They also are not egalitarian in pursuing careers or doing housework.

"Our results indicate that the institution of gender is so pervasive and entrenched that it shapes even the behaviors of individuals in such alternative living arrangements as cohabitation," said Sassler, associate professor of policy analysis and management in the College of Human Ecology.

Eventhough the findings are based on working-class couples, Sassler said that there is reason to think that middle-class cohabiting couples follow similar patterns, but more studies are needed to confirm this.........

West Nile Virus Antibody Binding Site

Scientists have learned the precise location where an antibody binds to the West Nile virus, and they have suggested a mechanism for how this antibody neutralizes the virus to prevent infection.

"Science doesn't yet fully understand exactly how neutralizing antibodies work," said Michael Rossmann, the Hanley Distinguished Professor of Biological Sciences in Purdue's College of Science. "This work has shown precisely where the antibody binds to the virus, and we now have a theory for how it interacts with the virus to disarm it. Perhaps we are starting to understand why this particular antibody can inhibit the infectivity of the virus, which is important to understand if a vaccine is going to be developed".

Purdue worked with scientists from the Washington University School of Medicine in St. Louis.

West Nile belongs to a family of viruses known as flaviviruses, which includes many dangerous insect-borne disease-causing viruses. The antibody attaches to a protein called an E protein, for envelope protein, which makes up the virus's outer shell. There are 180 copies of E proteins symmetrically arranged in 60 sets of three, forming a geometric shape called an icosahedron, which is made up of triangular facets.

The researchers, however, were surprised to discover that this antibody recognizes only two of the E proteins in each set of three, said Bärbel Kaufmann, a postdoctoral research associate working in the Rossmann lab.........

Did you know?Studies in monkeys and women suggest that unlike traditional estrogen therapy, a diet high in the natural plant estrogens found in soy does not increase the risk of uterine cancer in postmenopausal women, according to Mark Cline, D.V.M., Ph.D., an associate professor of comparative medicine at Wake Forest University Baptist Medical Center.